Asymmetric compounds obtained by asymmetric conjugate addition reaction to electron-deficient olefin such as nitroolefin compound, α,β-unsaturated carbonyl compound and the like are useful as intermediates for synthesizing amines, amino acids, pharmaceutical agents, agricultural chemicals, food additives and the like (e.g., Journal of the American Chemical Society, vol. 124, No. 44, p. 13097-13105 (2002)), and various production methods have been reported so far.
However, many of them require a stoichiometric amount of an asymmetric reagent (Journal of the American Chemical Society, vol. 124, No. 39, p. 11689-11698 (2002)), and most of the catalytic asymmetric conjugate addition reactions require strict reaction conditions or involve use of a metal catalyst (Tetrahedron, vol. 58, No. 29, p. 5773-5778 (2002)) and Synlett, special edition, p. 879-887 (2001)), which cause inefficient cost and operation, as well as environmental problems.
As a catalytic asymmetric conjugate addition reaction without using a metal catalyst, a Michael reaction to a nitroolefin compound using L-proline as a catalyst has been reported (Synlett, vol. 1, p. 26-28 (2002)). However, its stereoselectivity was unsatisfactorily low.
Furthermore, a Michael reaction to a nitroolefin compound using an asymmetric catalyst consisting of a magnesium salt and an asymmetric ligand has been reported (Journal of the American Chemical Society, vol. 121, No. 43, p. 10215-10216 (1999)). This method achieved high stereoselectivity, but is associated with limitations because it cannot be applied to bulky nucleophilic reagents having tertiary carbon etc., and the like.